The utility model provides an underground boosting water injection process pipe string, in order to overcome the defects of raised single-well water injection pressure, the inconsistence of an aboveground water injection system, more potential safety hazards for the maintenance of high-pressure water injection above the ground, heavy workload for the repairing and maintenance of an aboveground pump and the like when the aboveground water injection process is adopted in the traditional oil fields. An oil pipe (1), a screen pipe (3), a motor compensator (4), a motor (5), a protector (6), an electric submergible pump (8), an insert type sealing device (10), a packer (11), an oil pipe pup joint (13), a screen pipe (12), an oil pipe pup joint (13) and a screwed plug (14) of the pipe string are fixedly and sequentially connected from top to bottom; a radial suction hole (7) is arranged on the wall of the oil pipe (1) connected between the protector (6) and the electric submergible pump (8); and the screen pipe (12) is located at the position of a water injection layer (16) of the lower part of a well bore. The pipe string has the beneficial effects as follows: the problem of the insufficient pressure of a single-well water injection system is effectively solved; the maintenance cost of single-well water injection is reduced; and the oil-field development benefit is improved.